Liu Garden, located outside of the Chang gate of Suzhou, is a symbolic Suzhou style garden. It was built in 1593 by a retired officer. With an area of 23,310 sq.m.it is celebrated for its artistic way of dealing with the spaces between various kinds of architectural form. Buildings make up one third of the total area of the garden, the hall of which being the most remarkable in Suzhou. The garden was a tourist attraction since 1823 and recognized as the one of the four greatest Chinese gardens. Among the attractions here are the Nanmu Hall, known for its spaciousness, the Mandarin Duck Hall, exquisitely beautiful, and the "Peak Above the Clouds", actually a huge piece of rock, reputed to be the largest single rock south of the Yangtze River ever to be hauled from a lake. The garden is intricately designed providing a changing scene at every turn. It was recognized with nine other Suzhou gardens as United Nations World Heritage sites.